397 research outputs found

    On the Toxicity of Therapeutically Used Nanoparticles: An Overview

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    Human beings have been exposed to airborne nanosized particles throughout their evolutionary stages, and such exposures have increased dramatically over the last century. The rapidly developing field of nanotechnology will result in new sources of this exposure, through inhalation, ingestion, and injection. Although nanomaterials are currently being widely used in modern technology, there is a serious lack of information concerning the human health and environmental implications of manufactured nanomaterials. Since these are relatively new particles, it is necessary to investigate their toxicological behavior. The objective of this review was to trace the cellular response to nanosized particle exposure. Therapeutic application of selected nanoparticles together with their range of toxic doses was also reviewed. Effect of therapeutically used nanoparticles on cell membrane, mitochondrial function, prooxidant/antioxidant status, enzyme leakage, DNA, and other biochemical endpoints was elucidated. This paper highlights the need for caution during the use and disposal of such manufactured nanomaterials to prevent unintended environmental impacts

    STR-860: COST ANALYSIS OF CONICAL TANKS; COMPARISON BETWEEN REINFORCED CONCRETE AND STEEL

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    This paper provides a cost analysis case study to compare the effectiveness of using reinforced concrete versus steel as a construction material for conical tanks. Simplified design approaches, which were developed in previous investigations, are utilized to design a wide range of reinforced concrete conical tanks and steel counterparts having three different capacities (500 m3, 1750 m3 and 3000 m3). The cost analysis is conducted for each of the concrete and steel tanks. This analysis includes the cost of material, formwork, labour and life-cycle cost. Also, a general study of the effect of tank dimensions on the cost is provided. The results of this study show that steel conical tanks are considered as a more economical choice for medium and small capacity tanks, regardless their dimensions. On the other hand, for large capacity conical tanks (3000 m3), the tank dimensions govern which construction material (reinforced concrete or steel) is more cost effective

    NDM-534: SENSITIVITY OF WIND INDUCED DYNAMIC RESPONSE OF A TRANSMISSION LINE TO VARIATIONS IN WIND SPEED

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    This paper studies the dynamic behavior of a multi-span transmission line system under synoptic wind considering various speeds to determine the range of wind speeds in which the system experiences resonance. A finite element numerical model was developed for the purpose of this study. This model is employed to assess the dynamic behavior of a self-supported lattice tower line under various wind speeds. Dynamic Amplification Factor (DAF), defined as the ratio between the peak total response to the peak quasi-static response, is evaluated. It is found that conductors’ responses exhibit large DAF compared to the towers especially at low wind speeds (v ≤ 25 m/s). This results from the low natural frequency of the conductors (0.19 Hz) which is close to the wind load frequency while the natural frequency of the tower is equal to 2.36 Hz. In addition, the conductors’ aerodynamic damping decreases with the decrease of wind speed which leads to higher dynamic effect while the tower’s aerodynamic damping plays a minor role. The results of the dynamic analysis conducted in this study are also used to compare the gust response factors (GFT), defined as the ratio between peak total response to the mean response, to those obtained from the ASCE code (GFT-ASCE). It has been noticed that the gust response factors obtained from the ASCE code lead to conservative peak responses for both towers and conductors of the chosen line

    Exploiting the Synergy Between Gossiping and Structured Overlays

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    In this position paper we argue for exploiting the synergy between gossip-based algorithms and structured overlay networks (SON). These two strands of research have both aimed at building fault-tolerant, dynamic, self-managing, and large-scale distributed systems. Despite the common goals, the two areas have, however, been relatively isolated. We focus on three problem domains where there is an untapped potential of using gossiping combined with SONs. We argue for applying gossip-based membership for ring-based SONs---such as Chord and Bamboo---to make them handle partition mergers and loopy networks. We argue that small world SONs---such as Accordion and Mercury---are specifically well-suited for gossip-based membership management. The benefits would be better graph-theoretic properties. Finally, we argue that gossip-based algorithms could use the overlay constructed by SONs. For example, many unreliable broadcast algorithms for SONs could be augmented with anti-entropy protocols. Similarly, gossip-based aggregation could be used in SONs for network size estimation and load-balancing purposes

    Acción de extractos de hojas de olivo sobre marcadores del estrés oxidativo en diabetes mellitus inducida por estreptozotocina en ratas

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    Diabetes mellitus type two (T2DM) is one of the most extensive diseases in the world. Herbal therapy remains a possible adjunct therapy to sustain better glycemic control and reduce complications arising from diabetes. In order to evaluate the curative impacts of olive leaf extract (OLE) on streptozotocin (STZ)-induced diabetic rats, twenty-four Wistar male adult rats were divided into four equal groups; control, diabetic control (45 mg/kg STZ), normal rats treated with OLE (17.8 mg/kg b.wt.), and diabetic rats treated with OLE (45 mg/kg STZ + 17.8 mg/kg b.wt.). The OLE extract was investigated for in vitro antioxidant activity using the DPPH• assay. The phenolic, tannin, and flavonoid contents were determined. The activity of GPX, SOD, and GSH in RBC lysate, CAT in plasma and MDA in serum were measured. The OLE prevented the decrease in GSH and kept MDA around the normal range in the treated diabetic rats. The current study suggests that OLE might be used safely to ameliorate T2DM and its accompanying oxidative stress.La diabetes mellitus tipo dos (DM2) es una de las enfermedades más extensas en el mundo. La terapia con hierbas sigue siendo una terapia complementaria para mantener un mejor control de la glucemia y reducir las complicaciones de la diabetes. Con el fin de evaluar los efectos curativos del extracto de hojas de olivo (OLE) en ratas diabéticas inducidas por estreptozotocina (STZ), veinticuatro ratas Wistar machos adultos se dividieron en cuatro grupos iguales; control, control diabético (45 mg/ kg STZ), ratas normales tratadas con OLE (17.8 mg/kg b.wt) y ratas diabéticas tratadas con OLE (45 mg / kg STZ + 17.8 mg / kg b.wt.). El extracto OLE se investigó para determinar la actividad antioxidante in vitro usando ensayos DPPH•. Se determinaron los fenoles, los taninos y el contenido de flavonoides. Se midió la actividad de GPX, SOD y GSH en lisado de RBC, CAT en plasma y MDA en suero. El OLE evitó la disminución de GSH y mantuvo MDA alrededor del rango normal en las ratas diabéticas tratadas. El estudio actual sugiere que OLE podría utilizarse de forma segura para mejorar la DM2 y el estrés oxidativo que le acompaña

    Malus baccata var. gracilis and Malus toringoides bark polyphenol studies and antioxidant, antimicrobial and anticancer activities

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    Exploring new sources of polyphenols with biological activities that work against human diseases is the target of natural product studies. This study determined the polyphenol composition of the bark of Malus species M. baccata var. gracilis (Rehder) T.C.Ku and M. toringoides (Rehder) Hughes, using high-performance liquid chromatography with a diode-array detector (HPLC-DAD) analysis. The antiproliferative, cytotoxic, antioxidant and antimicrobial applications of these extracts, as well as the identified phenol, were studied. The HPLC-DAD analysis confirmed three polyphenols in the extracts out of the 21 screened compounds: protocatechuic acid, gallic acid, and catechin. The major constituents in M. baccata and M. toringoides were protocatechuic acid, at 3.16 and 7.15 mg 100 g1g^{-1} dry weight (DW), respectively, and catechin, at 5.55 and 6.80 mg 100 g1g^{-1} DW, respectively. M. baccata and M. toringoides bark extracts showed antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), β\beta-carotene bleaching, and ferric-reducing antioxidant power (FRAP) assays, which were attributed to the dominance of protocatechuic acid. The highest antiproliferative and cytotoxic e ects were against Jurkat cells. Against MCF-7 and Hela cells, there was necrotic cell accumulation in the early apoptotic as well as the late apoptotic phase. The bark extracts showed noticeable antibacterial e ects against Listeria monocytogenes, Bacillus cereus, and Escherichia coli. Protocatechuic acid showed comparable results to bark extracts. There were antifungal effects against Aspergillus ochraceus, A. niger, and Candida albicans, and the activities were higher than the commercial reagent. M. baccata and M. toringoides could be considered as a new source of phenolic acids, including protocatechuic acid with anticancer, antibacterial antifungal, and antioxidant-promising effects

    Polyphenol content and biological activities of Ruta graveolens L. and Artemisia abrotanum L. in northern Saudi Arabia

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    Natural populations of Ruta graveolens L. and Artemisia abrotanum L. in northern Saudi Arabia may be a rich source of natural polyphenols with potential biological activities. Therefore, tentative high-performance liquid chromatography–diode array detection was used to analyze the polyphenol contents of leaf extracts. R. graveolens mainly contained the phenolic acids chlorogenic acid and p-coumaric acid and the flavonoids rutoside and quercetin, whereas those of A. abrotanum mainly contained the phenolic acids isochlorogenic acid and rosmarinic acid and the flavonoid quercetin. Leaf extracts of both species showed antioxidant activities due to the presence of quercetin, chlorogenic acid, and p-coumaric acid as well as antiproliferative and cytotoxic activities against cancer cells, which may be attributed to necrotic cell accumulation during the early and late apoptotic periods. Both species also exhibited antibacterial activity, although the activity was higher in R. graveolens due to the high contents of quercetin and other polyphenols. Finally, both species exhibited antifungal activities, which were associated with specific polyphenols. This is the first study to confirm the richness of polyphenols and wide spectrum of biological activities in natural populations of R. graveolens and A. abrotanum in northern Saudi Arabia

    DESIGN, SYNTHESIS AND BIOLOGICAL EVALUATION OF SOME NEW SUCCINIMIDE, 2-IMINOTHIAZOLINE AND OXAZINE DERIVATIVES BASED BENZOPYRONE AS ANTICONVULSANT AGENTS

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    Objective: The objective of the present study was to synthesize novel benzopyrone derivatives with potential and safer anticonvulsant activity.Methods: New benzopyrone derivatives have been synthesized and characterized by spectral and elemental analysis. These compounds tested for anticonvulsant activity using the maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) screens (phase 1), which are the most widely employed seizure models for early identification of new anticonvulsant agents. Phase 2 including, neurotoxicity screening and quantitative determination of the median effective dose (ED50), median lethal dose (LD50) and protective index (PI) for the active compounds from phase 1.Results: Compound 12b possessed potent anticonvulsant activity with ED50 values of 94.75 and 70.7 mg/kg in the MES and scPTZ screens respectively, and had LD50 value of 2546 mg/kg after intraperitoneal injection to mice, which provide compound 12b with a wide protective index of 26.87 and 36.01 for MES and scPTZ screens respectively compared to the reference drug Phenobarbital with PI of 12.16 and 20.08, respectively. In addition, compound 12b exhibited mild neurotoxicity at the maximum administrated dose (200 mg/kg).Conclusion: Compound 12b possessed broad spectrum activity for the treatment of all types of seizures, with a wide protective index compared to Phenobarbital. Consequently, compound 12b can be selected as a new bio candidate lead for further study.Keywords: Benzopyrone, Succinimide, 2-Iminothiazoline, Oxazine; Anticonvulsant

    Saudi Rosmarinus offcinalis and Ocimum basilicum L. polyphenols and biological activities

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    Investigating the polyphenolic profile of natural Rosmarinus offcinalis and Ocimum basilicum populations may reveal essential compounds that have biological activities. Natural populations of R. offcinalis and O. basilicum in Northern Riyadh were investigated by HPLC-DAD analyses. Several polyphenols, including rosmarinic acid, gentisic acid, 3,4-dihydroxyphenylacetic acid, rutoside, and others, out of 38 screened were confirmed. Rosmarinic acid was the major polyphenol in both of R. offcinalis and O. basilicum. R. offcinalis methanolic leaf extracts contained other phenols such as gentisic acid while O. basilicum contained also 3,4-dihydroxyphenylacetic acid and rutoside as well as others. R. o cinalis showed higher antioxidant activities than O. basilicum using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and β\beta-carotene bleaching assays. These higher activities are associated with a higher composition of rosmarinic acid in leaf extracts. The antioxidant activities of O. basilicum were attributed to identified phenols of rosmarinic acid, 3,4-dihydroxyphenylacetic acid, and rutoside. There were antiproliferative and cytotoxic activities of leaf extracts, as well as identified polyphenols, against several cancer cells. These activities were attributed to the accumulation of necrotic and apoptotic cells in treated cancer cells with leaf extracts as well as identified polyphenols. The antibacterial and antifungal activities of leaf extracts were mainly attributed to 3,4-dihydroxyphenylacetic acid and rutoside in O. basilicum and rosmarinic acid and caffeic acid in R. offcinalis. This study proved that R. offcinalis and O. basilicum natural populations might be considered as promising sources of natural polyphenols with biological activities

    Polyphenol profile and pharmaceutical potential of Quercus spp. bark extracts

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    Targeted profiling of polyphenols in trees may reveal valuable sources of natural compounds with major applications in pharmacology and disease control. The current study targeted the profiling of polyphenols using HPLC-DAD in Quercus robur, Q. macrocarpa and Q. acutissima bark extracts. Free radical scavenging of each extract was investigated using antioxidant assays. Antimicrobial activities against a wide spectrum of bacteria and fungi were explored, as well as anticancer activities against di erent cancer cell lines. The HPLC-DAD analyses revealed the availability of several polyphenols in high amounts, including ellagic acid (in Q. robur) and caffeic acid (in Q. macrocarpa) in all three species. The bioactivity assay revealed high antioxidant activity in Q. robur compared to that of the other species, as well as phenolic standards. The three oak bark extracts showed clear antibacterial activities against most bacteria tested, with the highest antibacterial activities in the extracts of Q. robur. In addition, the three extracts showed higher antibacterial activities against Pseudomonas aeruginosa, Micrococcus flavus, and Escherichia coli compared to that of other bacteria. There were strong antifungal activities against some fungi, such as Aspergillus flavus, Penicillium funiculosum, and Penicillium ochrochloron. There were also noticeable anticancer activities against MCF-7, HeLa, Jurkat, and HT-29 cell lines, with the highest anticancer activity in the extracts of Q. robur. This is the first study that reveals not only novel sources of important polyphenols (e.g., ellagic acid) in Q. robur, Q. macrocarpa and Q. acutissima bark but also their anticancer activities against diverse cancer cell lines
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